Pencil cactus is a drought tolerant succulent that thrives in bright light and low moisture conditions. This cactus cannot tolerate frost so it will need to be brought indoors when outdoor temperatures fall below 45F. The cactus is fine outdoors during the summer months. Place in an area with bright direct light. The plant will tolerate full sun but may experience some stress if moved directly from an indoor location to full sun. Provide a transition period in a partially shaded area of a week or two between indoor and outdoor conditions. When actively growing, the plant will need to be watered 2-3 times a month depending on temperature and rainfall if outdoors. If the roots stay too wet, the cactus will not thrive. Adding a water soluble fertilizer once or twice a year during active growing periods will keep the cactus healthy.